I drive a 98 Subaru Forester with ~190,000 miles on it. This car is incredibly reliable and excluding the following incident I have never had a problem with it. The other day I went out to run some errands and when I came out of the store my car wouldn’t start. I turned the key and nothing happened. There was no sound from the engine or starter whatsoever, but the radio, air, etc. came on. It had started perfectly fine just an hour earlier that day. I had a friend come help me out and with a few strikes from a hammer on the starter the car fired right up so that appears to have been the problem. It’s been a few days now and it has started right up every time I’ve turned the key since. Was this incident just a fluke? Is this what they call a “dead spot” in the starter? Should I replace it or can I get away with just carrying a hammer and push starting if worse comes to worst?
This is exactly what you could call a “dead spot” on the armature of the starter, and eventually it will fail on you completely, and no amount of hammer blows will bring it back to life. Unless you enjoy the exercise of push starting your car, or alternatively searching for a hill to park atop so you can drive your car away, you need to replace your starter. The good news is that this is a definitive diagnosis for a bad starter. If the car wouldn’t start, and striking the starter with a hammer caused it to start, the problem is definitely the starter.
It is pretty common after 10 years that the starter solenoid contacts get bad enough to cause an intermittent problem like you described. The contacts can be replaced or you can replace the starter. The starter should be rebuilt anyways if you replace the contacts so most people just put in a remanufactured unit and save labor costs to fix the old one. Make sure your battery connections are clean also as a problem there can cause the kind of problem you had.